Warp knitting machine



Feb. 22, 1966 9, SCHEIBE 3,236,067

WARP KNITTING MACHINE Filed Aug. 17, 1964 5 Sheets-Sheet l Z5 z 4 I 26 FIG. 7

Feb. 22, 1966 w. H. SCHEIBE WARP KNITTING MACHINE 3 Sheets-Sheet 2 Filed Aug. 17, 1964 Feb. 22, 1966 w. A. SCHEIBE 3,236,067

WARP KNITTING MACHINE Filed Aug. 17, 1964 5 Sheets-Sheet 3 FIG. 4

United States Patent 3,236,067 WARP KNITTING MACHINE Walter Hugo Scheihe, Oherursel, Taunus, Germany, as-

signor to Knit-All Research AG, Zug, Switzerland, a corporation of Switzerland Filed Aug. 17, 1964, Ser. No. 390,066 Claims priority, application Luxembourg, Aug. 24, 1963, 44,325 6 Claims. (Cl. 66-86) The present invention relates to warp knitting machines in general and to such machines comprising latch needles which are guided in a trick plate situated behind the needles and a stitch comb, which is movable in a path substantially perpendicular to the plane of the needles and which engages between the needles to hold down the fabric during upward movement of the needles but is moved away from the needles, when necessary, so as to avoid interference with the feeding of yarn to the needles, in particular.

Such machines, which are known as Raschel machines, were originally used as slow-running machines in the production of knitted fabrics, but have recently been considerably improved and their working speed increased so that they have been widely adopted for the manufacture of tulle. It is known in such machines to locate the stitch comb at the latch side of the needles and to mount on it a stop for the needle latches.

It is one object of the present invention to provide a warp knitting machine which increases the working speed of the Raschel machine.

It is another object of the present invention to provide a warp knitting machine, which includes means for moving the trick plate in a path substantially parallel to the path of movement of the needles and in such manner that the trick plate moves substantially in a direction opposite to that in which the needles move, particularly when the needles are in the vicinity of the top dead center position. As a result, the following advantages are obtained.

The needles have to be raised to a level above the edge of the trick plate sufficient to ensure that the new loops formed in the hooks of the needles during the preceding downward movement will be guided over the open needle latches and stripped from the latches. By arranging for the trick plate to be moved downwardly as the needles move upwards and approach the top dead center position, the upward travel required of the needles is reduced and the accelerating forces on the needles are also reduced. The stress on the operating mechanism is, there fore, less and the springs counteracting the accelerating forces can be made weaker and smaller.

Another factor which opposes an increase in speed of the Raschel machine is the knocking over operation, that is to say the slipping of the loops on the needles over the hooks of the needles when the loops have slid over the raised needle latches during the downward movement of the needles. Decrease in the duration of the knocking over operation increases the tension on the yarn and this has imposed a limit.

It is, therefore, still another object of the present invention to provide a warp knitting machine, wherein the time available for knocking over is increased by moving the trick plate, as the needles are approaching the bottom dead center position, at which knocking over is comice pleted, first upwardly and then downwardly to the same extent as the needles. This has the same effect as when the needles dwell in the bottom dead center position with a stationary trick plate and increases the time available for knocking over.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is a vertical section through the machine, designated in accordance with the present invention;

FIG. 2 is an elevation, on a larger scale, of the needlebar drive of the machine disclosed in FIG. 1, in the top dead center position;

FIG. 3 is an elevation, on a larger scale, of trickplate drive of the machine disclosed in FIG. 1, likewise in the top dead center position;

FIG. 4 is a graph disclosing the needle movement;

FIG. 5 is a graph disclosing the trick-plate movement;

FIG. 6 is an elevation, on a larger scale, of another embodiment of the needle-bar drive; and

FIG. 7 is a section along the lines 77 of FIG. 1.

Referring now to the drawings, and in particular to FIG. 1, the warp knitting machine is a known type and a machine of this type is more fully described in US. Patent No. 2,744,398, dated May 8, 1956. Only the more important parts, therefore, are shown in FIG. 1. The machine frame 1 is supported by feet 2 and includes end plates 3, between which extends a tubular support 8 carrying bearings 7 for a shaft 5 on which are mounted guide bars 24 and 24a which carry yarn guides 16 and 16a, respectively.

The yarn is taken to the yarn guides 16 and 16a from spools 25 and 26 over tensioners 30 which are pivotallyv mounted on brackets 31 carried by the tube 8.

Also extending between the end plates 3 are a cam shaft 46 and a shaft 52, which are journalled in the end plates 3.

The cam shaft 46 carries a belt pulley which is driven by a belt 43 from a belt pulley 44 of an electric motor 42, having a. regulator 37 which is adjustable by a hand wheel 38. The motor 42 is provided with a safety switch 41. The frame 1 carries brackets 9 which support a shaft 10, provided with a hand wheel 40 and geared to the cam shaft 46 so as to enable the machine to be turned by hand. A control bar 39, supported by thebrackets 9 and further brackets 11, extends for the whole length of the machine and is displaceable to actuate a circuit-breaker for stopping the machine.

Bell cranks 53 (FIGS. 1 and 2) pivoted to the shaft 52 carry cam rollers 54 which cooperate, respectively, with cams 47 and 47a on the cam shaft 46. The bell cranks 53 are connected by rocking levers 51 to a needle bar carrying needles 50a which receive from the cam shaft 46 an arcuate oscillating movement, as indicated at 64.

FIG. 4 shows the movement imparted to the needles 50a during each machine cycle, that is to say during one revolution of the cam shaft 46.

A stitch comb 55 is disposed adjacent the latches of the needles 50a and is carried by rocking levers 59 (FIG. 1) which are connected to hell cranks 57 which are pivoted to a shaft 58 extending between the end plates 3.

Each bell crank 57 carries a pair of cam rollers 56, which, like the cam rollers 54, engage a pair of cams 57 Patented Feb. 22', 1966- e and 570, which are mounted on the cam shaft 46 and move the stitch comb 55, as indicated at 63, towards and away from the needles 50a, so that it will hold down the knitted fabric during the upward travel of the needles 50a and withdraw from the needles 50a to make room for the laying of yarn from one needle to another under control of the guide bars 24 and 24a. The stitch comb 55 has pinshaped stops 55' arranged in the path of the latches 50b. The cam shaft 46 also carries other cams 46 and 46a, which rock the guide bars 24 and 24a about the shaft by means of cam levers 60, mounted on the shaft 52, and linkage 61, 62. The guide bars 24 and 24a can also be shifted along the shaft 5' by a drive mechanism (not shown) of any suitable structure.

The needles 50a are guided in a trick plate 65 (FIGS. 1 and 3), which is carried by rocking levers 66 mounted on the shaft 52 and connected to bell cranks 67. These carry cam rollers 68 which cooperate with earns 69 and 70 on the cam shaft which impart to the trick plate 65, during each machine cycle, the upward and downward motion illustrated in FIG. 5. As will be apparent from FIGS. 4 and 5, during the major portion of the upward movement of the needles towards their highest position, the trick plate 65 is moving downwardly. As a result, the distance which the needle bar 50 needs to travel, the acceleration of the moving parts, and the accelerating forces are reduced. The machine may, therefore, be run faster, without strengthening the levers, rollers, cams and bearings, than is possible with a machine having a stationary trick plate.

FIGS. 4 and 5 also show that when the needles 50a are moving towards their lowest position, the trick plate 65 first moves upwardly with the effect described above. However, as the needles 50a near their lowest position, the trick plate 65 moves downwardly and, therefore, in the same direction as the needles 500. This has the same effect as when the needles dwell in the bottom dead center position with a stationary trick plate and increases the time available for knocking over, that is to say it increases the angle of rotation of the cam shaft 46 which is available for knocking over. This, again, facilitates increase in the speed of the machine and permits the cams to be so designed as to impart less acceleration. Less tension is, therefore, imposed on the yarns, the risk of yarn breakage is avoided and a uniform, firm fabric, free of faults is assured even with a high machine speed.

The finished fabric is pulled down over the trick plate 65 in the usual manner and conveyed by intermediate rollers 33 and 34 to a take-up roll 35 (FIG. 1).

In order to hold the fabric stretched between the trick plate 65 and the intermediate roller 33 during the upward and downward motion of the trick plate 65, it is taken over a tension roller 12, which is mounted in two doublearmed levers 13, which are pivoted on an axis 14 and biased by tension springs 15, secured to one end of the remote one of the levers 13.

Instead of using the above-described cam drive, the needle bar 50, the trick plate 65 and the stitch comb 55 may be actuated by a socalled Roman drive, such as that described in British Patent No. 525,255. Such a drive, as applied to the needle bar 50, is shown in FIG. 6. It consists of two shafts 19 and 20 which are coupled by meshing gearwheels 71 and 72 and carry eccentrics 48 and 49, respectively. The shaft 19 runs twice as fast as the shaft 20, and one of these shafts is driven by the electric motor 42 by any conventional means (not shown). The eccentricity of the eccentric 49 on the shaft 20 is twice as great as the eccentricity of the eccentric 48 on the shaft 19. When the eccentric 49 is in its bottom dead center position, the eccentric 48 is also in its bottom dead center position. The connecting rods 73 and 74 of the eccentrics 48 and 49- drive a two-armed lever 75 to which is pivoted a link 76. The point of articulation of the link 76 to the lever 75 is twice as far away from the point of connection of the connecting rod 73 to the lever 75 as it is from the point of connection of the connecting rod 74. The link 76 is pivoted at its upper end to the rocking lever 51. A guide link 77, which is pivoted at one end to the link 76 and at the other to a fixed point 78 of the frame of the machine, forms a parallelogram linkage with the link 76 and the rocking lever 51. By appropriate selection of the eccentricities of the eccentrics 48 and 49, the ratio of the lever arms of the two-armed lever 75 and the relative angular positions of the eccentrics 48 and 49, the needle bar 50 is caused to execute a movement such as is shown in FIG. 4, during each revolution of the shaft 20. By varying said ratios and angular positions, the path of the movement of the needle bar 50 of the machine can be varied within wide limits and adapted to the motion required. Similar considerations apply, of course, to the movements of the trick plate and the stitch comb 55.

The Roman drive produces a more favorable distribu tion of forces than the cam drive shown in FIGS. 2 and 3. As a result, when the Roman drive is used to drive the trick plate 65, it is possible to mount the intermediate rollers 33 and 34 (FIG. 1) on extensions of the rocking levers 66 which'carry thetrick plate 65, so allowing them to participate in the movement of the trick plate, and eliminating the tension roller 12. Furthermore, the link 76 and the guide link 77 may be replaced by a piston rod guided in a cylinder and carrying a bar to which the trick plate 65 is secured and on which the intermediate rollers are mounted.

While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A warp knitting machine comprising a frame, a trick plate movably disposed in said frame, a plurality of latch needles movably disposed in said frame and guided in said trick plate, the latter being positioned behind said latch needles, a stitch comb mounted in said frame for a reciprocating movement in a path substantially perpendicular to the plane of the needles, means for reciprocating said latch needles within said frame, and means for moving said trick plate in a path substantially parallel to the path of movement of said latch needles, and means causing said trick plate to move substantially in a direction opposite to that of the movement of said latch needles.

2. A warp knitting machine comprising a frame, a trick. plate movably disposed in said frame, a plurality of latch needles movably disposed in said frame and guided in said trick plate, the latter being positioned behind said latch needles, a stitch comb mounted in said frame at the latch side of the needles for a reciprocating movement in a path substantially perpendicular to the plane of the needles and including stop means for the latches of said needles, means for reciprocating said latch needles within said frame, and means for moving said trick plate in a path'substantially parallel to the path of movement of said latch needles, and means causing said trick plate to move substantially in a direction opposite to that of the movement of said latch needles.

3. The warp knitting machine, as set forth in claim 1, in which the movement of the trick plate in a direction opposite to that of the movement of said latch needles is effected during that position of the machine cycle in which the needles are in the vicinity of the top dead center position.

4. The warp knitting machine, as set forth in claim 1, which includes means causingsaid trick plate to move substantially in the same direction as that of the movement of said latch needles, when the latter are in the: vicinity of the bottom dead center position during knock.- 1ng over.

5. The warp knitting machine, as setfqrthincla m.

which includes a tension roller flexibly mounted below the upper edge portion of said trick plate and disposed adjacent said trick plate, the produced fabric being laterally withdrawn below the upper edge of said trick plate over said flexibly mounted tension roller, so that said fabric can stretch during the upward movement of said trick plate.

6. The warp knitting machine, as set forth in claim 1, which includes supporting means for said trick plate mounted on said frame, and rollers, rotatably mounted on said supporting means, for withdrawing the produced fabric, so that the distance of said rollers from the upper edge of said trick plate remains constant.

References Cited by the Examiner UNITED STATES PATENTS 2,744,398 5/ 1956 Scheibe 6686 5 FOREIGN PATENTS 864,602 1/ 1953 Germany. 930,106 7/1963 Great Britain.

DONALD W. PARKER, Primary Examiner. RUSSELL c. MADER, Examiner. 

1. A WARP KNITTING MACHINE COMPRISING A FRAME, A TRICK PLATE MOVABLY DISPOSED IN SAID FRAME, A PLURALITY OF LATCH NEEDLES MOVABLY DISPOSED IN SAID FRAME AND GUIDED IN SAID TRICK PLATE, THE LATTER BEING POSITIONED BEHIND SAID LATCH NEEDLES, A STITCH COMB MOUNTED IN SAID FRAME FOR A RECIPROCATING MOVEMENT IN A PATH SUBSTANTIALLY PERPENDICULAR TO THE PLANE OF THE NEEDLES, MEANS FOR RECIPROCATING SAID LATCH NEEDLES WITHIN SAID FRAME, AND MEANS FOR MOVING SAID TRICK PLATE IN A PATH SUBSTANTIALLY PARALLEL TO THE PATH OF MOVEMENT OF SAID LATCH NEEDLES, AND MEANS CAUSING SAID TRICK PLATE TO MOVE SUBSTANTIALLY IN A DIRECTION OPPOSITE TO THAT OF THE MOVEMENT OF SAID LATCH NEEDLES. 